Adjusting device for chair-backs.



ECUTORS.

Patented Nov; 13, 1917.

UNITED STATES gPATENT OFFICE.

FRAN K RITTER,YOF RCHESTER, ,NEW YORK; ADELINA RITTEYR'SHUMWAY AND LAURA A. RITTER EXECUTORS 0F SAID. FRANK: RITTER, DECEASED. i

Y ADJUSTING DEVICE FOR CHAIR-BACKS.

Specification of Letters Patent. Patnted NOV, 13, 191'?, Original application filed November 14, 1911,' Serial No. 660,232. Patented May 4, 1915, No."1,'137,903.

Divided andthis application filed August 25,1913. Serial No. 786,384.

y To all whom t may concer-n: 5 Y

Be it known thatw I', FRANK'RITTER, of Rochester', in the county Yof Monroe and State of New` York, have invented ycertain new and useful Improvements in Adjusting Devices for'Chair-Baclrs; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this specification, and to the reference-numerals marked thereon.

My present invention relates to chairs particularly of that type adapted to be used by dentists and it has for its object to provide a new and improved formof adjusting mechanism for the back rest whereby it may be tilted to fit the hollow of the occupants back and be retained in this position during the tilting of the chair back from one position of adjustment to another. To these and other ends the invention consists in certain improvements and combinations of parts all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawings:

Figure l is a side elevation of a chair back illustrating the adjusting mechanism constructed in accordance with my present invention;

lig. 2 is a rear elevation of the back rest, an

Fig. 3 is a detailed view illustrating the operation of the adjusting devices and showing them in another position of adjustment.

Similar reference numerals in the several figures indicate the same parts.

This application is a division of a prior application filed by me November 14th, 1911, bearing the Serial No. 660,232 relating to dental chairs.

In illustrating the present invention I have shown it applied to a dental chair comprising the seat frame 1, which carries standards 2 on which is pivotally supported the back frame 3 having the forwardly eX- tending arms 4 pivoted to the standards 2. The back of the chair is capable of being rotated fromV a vertical to a horizontal position and said back in addition tothe frameS also includes two telescoping members 5 and 6 which are respectively connected to the back frame and seat frame by the pivots 5a and afAny desired form of locking mechanism may be employed to retain the chair back in its adjusted angular position and in the present arrangement of the parts the locking devices arearranged on the member 5 and cooperate with therod or member, the means for controlling them being indicated by the handle 7. The back rest as distinguished from the back frame of the chair is thel portion 8 which is engaged by the occupant ofthe chair and itV preferably'comprises an open .metallic frame 9, which is suitably upholstered, and hasatits upper edge a rearwardly extending arm y10, pivotedv at 10a, eitherto the back frame 3 or to the adjustable-slide 1-1, movable longitudinally on the said frame for the purpose of carrying the ,back-rest toward `or from the chair Y seat. 12 indicates the handle of the locking mechanism employed for retaining the slide 11 in place. The latter may also carry a head rest 13 which is mounted upon suitable supports permitting its universal adjustment.

It is particularly desirable in a dental -chair to provide means for adjusting the angle of the back rest relatively to the back frame so that the lower portion thereof may fit snugly and comfortably the hollow portion of theoccupants back, and with this object in view I pivot the frame 9 at its upper end and upon its lower edge I provide a brace 14, the free end of which engages a` portion of the back frame of the chair, as for instance, the member 5. The brace 14 is provided with a notched portion 15 which is curved slightly, as illustrated, and with which coperates the pawl 6, also carried on the back rest. Both the brace and the pawl I being pivotally mounted at 14a and 16a between a pair of upwardly extending ears 9a on the lower rail of the back rest, as shown particularly in Fig. 2. The pawl 16 coperates with the ratchet teeth 15 for the purpose of holding the lower end of the back rest in various positions of adjustment and the pawl preferably carries handle 17 projecting laterally from its opposite sides, by which it may be elevated to release the brace. By this adjustment of the parts the back rest may be adjusted in the first instance to comfortably iit the torso of a person seated in the chair, when in an upright position; and both the brace and pawl being gravity operated and the latter automatically falling into engagement with the ratchet teethv l5 the' operator is only required rest vtoward him into the desired position.

lThe arrangement of the parts is'also such that they occupy only a small space and permit the lower end of the back rest to lie closely to the parts comprising the back frame of the chair, as shown in Fig. 1or moved outwardly therefrom as shown in Fig. 3.

` I claim as my invention:

Vl. In a chair, the combination with a back frame and a movable back rest thereon, of a brace' arm attached to the lower end of the back rest and projecting upwardly therefrom and having its free end in Contact with the back frame and a pawl also attached to the back rest adjacent said brace arm and vcooperating'therewith to sustain the back rest in various angular positions of adjustment relatively to the back frame.

2. In a chair, the combination with a back frame and a movable `back rest thereon, of a brace arm pivoted on the lower end of the back rest and extending upwardly therefrom having its free end engaging the back frame, said arm having a plurality of ratchet teeth on its forward edge, and a pawl attached to the back rest above and in proximity to the pivot of the brace arm and adapted to automatically coperate with the teeth thereon. Y

3. In achair, the combination with a back frame and a movable back rest pivoted thereto at its upper end and composed of an open frame piece having a bottom rail, and a pivot lug on the rail projecting upwardly in the frame opening, of a brace arm pivoted at the bottom of the lug and arranged with its free end extending upwardly in Contact with the back frame, a pawl also pivoted'to the lug above the pivot of the arm .and having its Vfree end engaging the arm to Vhold it in its adjusted angular position to support the lower end of the back rest.

FRANK RITTER.

Vitnesses: Y f

CHARLES W. FERTIG, G. VILLARD RICH.

Copies of this -patent may be obtained for five centseach, byaddressing the Commissioner of Patents. Washingtonyl). C. 

